1. Field of the Invention
The present invention relates to a printed circuit board (PCB), and more particularly, to a flexible printed circuit board (FPCB).
2. Discussion of the Related Art
A printed circuit board (hereinafter, referred to as ‘PCB’) is used to electrically connect or support electronic components on a blank substrate according a circuit design of electric wiring or traces. The PCB may be largely classified into a rigid PCB (RPCB), a flexible PCB (FPCB), and a special board.
The FPCB allows an efficient arrangement in a limited space of the electronic device, and also enables small-sized and light-weight electronic device. Furthermore, the FPCB is advantages in that it can be designed in various ways. Owing to the aforementioned many advantages, a demand for the FPCB is rapidly increased.
However, when the heavy electronic components are placed on the FPCB, or the large force is applied to the FPCB, the FPCB is apt to be severed due to its low structural strength. In order to overcome this problem of low structural strength, a thick film may be adhered to the related art FPCB so as to enhance the strength of the FPCB. However, the thick film adhered to enhance the strength of the related art FPCB may cause the deterioration of thermal properties. Furthermore, a manufacturing cost is increased due to an additional process for adherence of the thick film.
In case of a backlight unit of an LCD device, light-emitting diodes (hereinafter, referred to as ‘LEDs’), which are used as a light source for the backlight unit, are placed onto the PCB. Recently, there is the increased demand for the FPCB in the backlight unit of the LCD device, due to the following disadvantages.
In case of the LCD device using an edge-type backlight unit with LEDs, heat might be concentrated on the PCB on which the LEDs are arranged. In this respect, the PCB is formed of a metal material with great heat-radiation properties. While the metal PCB has the great heat-radiation properties, a width (W) of the metal PCB is inevitably increased due to a connector 110 arranged on the PCB 100, as shown in FIG. 1A. As a result, a thickness of the LCD device is also increased due to the increased width of the metal PCB.
For decreasing the thickness of the LCD device, the PCB may be formed of another material instead of the metal material. However, if using the PCB of another material instead of the metal material, as shown in FIG. 1B, heat-radiation areas 130 of LEDs are limited to partial portions of the LCD device 120 using the edge-type backlight unit with LEDs. Thus, heat generated from the LEDs is not smoothly transmitted, whereby efficiency of LEDs may be deteriorated, or the LCD device may be warped or distorted.